CPWR Hazard Alert: Trenches

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CPWR - The Center for Construction Research and Training

Summary Statement

This CPWR Hazard Alert points out the very real dangers of trench collapse that lead to 3 worker deaths a month, on average, in the U.S. Trenches must be shored, sloped/benched or fitted with a trench box. The three steps to prevent this outcome are noted: 1) find the competent person, 2)work in protected areas, and 3)check your escape.
2012

TRENCHES

Trench

Am I in danger?

If you enter a trench that isn’t...

  • shored
  • sloped/benched or
  • fitted with a trench box

And there isn’t...

  • a way to escape if it collapses and
  • a “competent person”

Then the answer is YES.

An unprotected trench can collapse in less than a second.

You could die in minutes from a trench collapse... even if your head and arms are above the dirt.

How can a trench kill me?

Dirt is heavy. Really heavy. One cubic yard of dirt is the weight of a mid-sized car.

Illustration comparing the weight of one cubic yard of dirt to a mid-sized car

The weight of the soil is so heavy that it will crush you. Trench walls may look stable, but DON’T TRUST them. On average, more than three workers die every month from a trench collapse.*

*The Construction Chart Book, p. 39. CPWR. 2008.

Before you go in...

1. Find the ‘competent person’

OSHA says every excavation job must have a person appointed by the employer as the competent person. This person must inspect the trench every day before work, after rain and when conditions change. When there is a problem, the competent person has the authority to stop work and fix it.

The competent person on a worksite with a trench

2. Work only in protected areas

Work only inside the trench box or shored areas of the trench if the trench is not sloped or benched. Wear your hardhat.

Do not follow this worker: no ladder, no hardhat, not working in the trench box

Don’t follow this worker above: No ladder, no hardhat, not working in the trench box.

3. Check your escape

If only takes a second for a trench to collapse, so always be aware of your escape route. If you are in a trench 4’ or deeper, you must be within 25’ of a ladder, ramp or stairway.

Make sure you are within twenty-five feet of a ladder such as this

Find out more about safe work in trenches:

Short OSHA video on prevention of trench collapse: www.youtube.com/watch?v=cFYkeT0Yk6k

OSHA’s Quick Card on Trenching: www.osha.gov/Publications/trench/trench_safety_tips_card.pdf

OSHA’s definition of a competent person: www.osha.gov/SLTC/competent person/index.html

Don't end your life in a trench. Work safe. Every day.

If you think you are in danger:

Contact your supervisor. Contact your union.

Call OSHA 1-800-321-OSHA


Find out more about construction hazards.

Get more of these Hazard Alert cards – and cards on other topics.

Call 301-578-8500